The invention relates to a high-frequency circuit comprising at least a field-effect transistor comprised, in contact with an active zone, of gate, drain and source electrodes, the gate electrode receiving a high-frequency input signal and the source and drain electrodes being moreover provided with biasing and charging circuits, and the source electrode being connected to ground through a load.
The invention is used in amplifier stages or oscillators in high-frequency fields.
A high-frequency circuit of the type described above is known from the article "A fully-integrated, 0.5. W; 2 to 6 GHz MMIc amplifier", by B. MAOZ et al, during the "17.sup.th European Microwave Conference, Ergife Palace Hotel, Rome, Italy, 7.sup.th 11.sup.th Sept. 1987", published in "Conference Proceedings Microwave exhibitions and Publishers LTD, pp. 261-266".
This article discloses an integrated amplifier formed by two stages. Each stage comprises a field-effect transistor, with interleaved gate. The gate is consequently formed by a plurality of fingers which at one end are connected to a large-surface gate contact area, and to which the high-frequency input signal of the stage and also a biasing circuit of the LC type are applied. The drain is also formed by a plurality of fingers, which alternate with the gate fingers, which are connected, at their end opposite the gate contact area, to a large-surface drain pad, to which a biasing circuit of the LC type is applied and where the high-frequency output signal of the stage is picked off. The source is directly connected to ground.
Whatever its design, this amplifier provides, for each stage, a maximum gain which is less than or equal to the gain of a non-loaded transistor identical to the transistor forming it.